There's a way to avoid that: have it set up at HWC or at the house of one of our owners (but not me )...

Yeah, but then you're really just raffling off PPD rather than the machine itself. What you're suggesting, unless I am mistaking you, is basically like selling cloud compute time in raffle form. That would probably reduce the scope of interest and make it harder for the would-be seller to recoup value.

After all, the primary goal for something like this would be to sell a piece of equipment that is simply cost-prohibitive for most people. That a raffle might enable this makes it a good idea unto itself. That a raffle would also contribute to team unity, PPD retention, and that kinda stuff are all just sorta bonuses. Really awesome bonuses.